Bridgestone Tire Company Limited

Bridgestone Corporation

Bridgestone Corporation 10-1

Hikaru Tansei

Kenichi Motomura

Hiroshi Ogawa

Yukimasa Yamada

Mamoru Mamada

Masaru Abe

Masao Nakamura

Masayuki Ohashi

Hiroyoshi Takigawa

Yasuyoshi Kawaguchi

Yoichi Honbo

Muneyoshi Maeda

Mitsunori Wada

Kazuyuki Endo

Katsuhiko Kajimoto

Mikio Nomata

At lest a portion of a core assembly for a pneumatic tire, which is mounted on an outer surface of a well portion of an annular rim to which the pneumatic tire is attached, is formed from an elastomer material. The radial height of the core assembly in a condition where an inner surface of a crown portion of the tire is in contact with an outer peripheral surface of the core assembly is set in a range of from 40% to 70% of the normal height of the tire, and the width of the outer peripheral surface of the core assembly is set at 0.5 or more times the radial height of the core assembly.

Core assembly for pneumatic tire and pneumatic tire assembly

A pneumatic tire is disclosed, which comprises a carcass ply, two vulcanized rubber composition layers arranged radially inside the carcass ply, and a continuous layer of a sealing material arranged between the two vulcanized rubber composition layers. The sealing material has a viscosity of not more than 6.times.10.sup.4 poises at 60.degree. C. Bonding portions are formed through the continuous layer, and discontinuously bond two vulcanized rubber composition layers.

Pneumatic tires with apertured puncture sealing layer

A pneumatic tire comprising a tread divided into at least three ribs by at least two main wide grooves extending substantially in a circumferential direction of the tire, wherein a shoulder rib arranged at an outermost end portion of the tread is divided in an axial direction parallel to an axis of rotation of the tire into at least two shoulder rib portions; and between two adjacent shoulder rib portions of said at least two shoulder rib portions, an outer surface of an outer shoulder rib portion is radially inwardly disposed with respect to an extension line of an outer surface of an inner shoulder rib portion arranged inwardly of the outer rib portion. A plurality of sipes may be formed in the vicinity of an outer end of at least one shoulder rib portion other than an outermost shoulder rib portion. Further, a plurality of sipes are formed in the vicinities of outer ends of at least two rib portions other than an outermost rib portion, the quantity of siping being gradually reduced in the axial direction.

Pneumatic tire tread with divided shoulder

Automobile tire

A pneumatic tire comprising a tread divided into at least three ribs by at least two main wide grooves substantially extending in a circumferential direction of the tire, wherein a shoulder rib of the ribs arranged at an outermost end portion of the tread is divided in an axial direction parallel to an axis of rotation of the tire into at least two rib portions; and between two adjacent rib portions of the rib portions, an inner end of an outer surface of an outer rib portion is connected through an outer surface of a circumferentially extending sloped portion to an outer end of an outer surface of an inner rib portion so that the outer end of the outer surface of the outer rib portion is lower than the inner end of the outer surface of the inner rib portion.

Pneumatic tire tread with recessed shoulder portion

A pneumatic tire excellent in uneven wear resistance, is provided with a tread pattern which comprises a plurality of main grooves extending zigzag along the circumference of a tread, numerous transverse grooves linearly extending in at least one land portion defined between the adjacent main grooves and between the main grooves at a depth shallower than the main grooves, each one of said transverse grooves being provided in every one zigzag pitch of the main groove, a number of blocks separatedly formed and arrayed by the main grooves and the transverse grooves, and a pair of notch grooves provided in each of the blocks and branching from the main grooves sandwiching the block for mitigating difference in rigidity between the edge portions and the central portion of the block.

Pneumatic tire excellent in uneven wear resistance

Vehicle tire

A heavy duty pneumatic radial tire is disclosed, which comprises a carcass composed of at least one rubberized ply containing cords arranged substantially in a radial plane of the tire and a belt superimposed about a crown portion of the carcass just beneath a tread and composed of at least three rubberized belt plies. In this tire, metal cords of a first belt ply nearest to the carcass among the above belt plies are arranged at an angle of 25.degree.-50.degree. without crossing with metal cords of a second belt ply near the carcass next to the first belt ply with respect to a central circumferential line of the tire, and metal cords of the second belt ply and a third belt ply near the carcass next to the second belt ply, a tensile strength of each of which being 1.5-2 times that of the metal cord of the first belt ply, are arranged at an angle of 10.degree.-30.degree. and smaller than the cord angle of the first belt ply with crossing with each other between these two belt plies with respect to the central circumferential line of the tire.

Heavy duty pneumatic radial tires

A heavy duty pneumatic tire is disclosed, which has a tread pattern formed in a tread divided into a plurality of lands by a plurality of longitudinal grooves extending circumferentially of the tread, among which each of a first land in at least a side edge region of the tread and a second land adjacent thereto has an arrangement of blocks defined by transverse grooves arranged at a substantially equal interval in the circumferential direction of the tread. In this tread pattern, each block of the first land is arranged in zigzag form opposite to two adjoining blocks of the second land, the opposed groove walls of the longitudinal groove defining the first and second lands have a minimum distance corresponding to not more than 3% of the tread width, and the remaining longitudinal groove(s) located in a center of the tread or sandwiching the central land of the tread has a groove width corresponding to 4-10% of the tread width.

Heavy duty pneumatic tires

A heavy duty pneumatic tire includes a tread surface divided along circumferential directions by at least two zigzag tread grooves to form a plurality of circumferential zigzag ribs whose at least one side edge is formed with a plurality of narrow cuts opening into the tread grooves and substantially in parallel with an axial direction of the tire. According to the invention, lengths and/or depths of the narrow cuts are gradually reduced from the cuts in the extending corners to the cuts in the retracting corners of the ribs, or the narrow cuts are inclined relative to radial surfaces of the tire passing through openings of the cuts to make angles with their radial surfaces, the angles being progressively larger as the cuts are nearer the extending corners to mitigate railway wear of the tire without sacrificing other wear-resistant properties.

Heavy duty pneumatic tire

A pneumatic radial tire for heavy vehicles is disclosed. This tire comprises a carcass composed of at least one ply of cords arranged in a substantially radial plane inclusive of the rotary axis of the tire with a turnup portion thereof, and a plurality of reinforcing layers for bead portion each containing cords crossed with the cords of the carcass ply. Among these reinforcing layers, reinforcing layers having heights which are different in radially upward end as measured from a reference line parallel to the rotary axis of the tire passing through the center of a bead core toward the radial direction of the tire and having cords with substantially the same modulus of elasticity are crossed with each other such that the cords of the reinforcing layer are inclined at a larger angle with respect to the radial plane of the tire as the height of the radially upward end becomes lower.

Pneumatic radial tires for heavy vehicles

A pneumatic radial tire for heavy load vehicles including an improved bead portion reinforcing construction constructed such that the cords of a reinforcing layer along the outside of a carcass ply are inclined on a circle formed by the upper end of a turn-up region of the carcass ply at an angle of 50.degree. to 70.degree. with respect to the radial plane of the tire and have an air gap ratio .delta. of 38% to 60% measured at a region where the cords of the reinforcing layer cross with a line tangent to a curved surface of a rim flange and extending in parallel with the rotary axis of the tire and given by the following formula ##EQU1## where b is a distance between two midlines of two adjacent cords, measured perpendicular to the cords, and c is a cord diameter.

Growing community of inventors

Kodaira, Japan

Hikaru Tansei